The present invention relates generally to the field of voice tele-communication, and more specifically to the field of aircraft voice tele-communication by flight crews using the public switched telephone network.
In the field of aircraft communication, flight crews use ultra high frequency (UHF), very high frequency (VHF) and high frequency (HF) radios for communication with other aircraft and ground controllers. UHF communications are generally reserved for military or government owned aircraft. Civil commercial aircraft typically have two or three VHF radios and one or more HF radios. Recently, for over water routes where UHF, VHF and HF communications are impossible or less reliable, provision has been made for aircraft flight crews access to satellite communication (SATCOM). These UHF, VHF, HF and SATCOM radio systems provide reliable two way voice communication supporting flight safety, flight direction and flight control with specific frequencies or channels assigned for specific communication purposes and users. For example, one VHF frequency may be assigned for ground communication between an aircraft on the ground and a ground control tower at an airfield as the aircraft moves about the airfield ramp and taxiways. Another VHF frequency may be assigned for departure communication between the aircraft and the tower to provide direction and control immediately after takeoff. Once airborne, the aircraft will be assigned another VHF frequency for flight direction and control by a sector controller while operating in the airway flight structure.
For reasons of flight safety, at least one crew member is required to monitor the primary assigned aircraft control frequency which may be UHF, VHF, HF or SATCOM, and usually both crew members monitor that primary assigned aircraft control frequency in addition to selected secondary frequencies. On the flight deck, flight crews typically communicate on the UHF, VHF, HF and SATCOM radios with a headset, which contains an integral speaker and microphone. Alternatively the flight crew may use a cockpit speaker and hand microphone. The flight crew member may independently select any of the available UHF, VHF, HF or SATCOM radio transceivers for communication through a selection panel or console. In addition to transmitting and receiving on a primary frequency or channel with one radio, the flight crew member may monitor other secondary radio frequencies or channels. Transmission access to these UHF, VHF and HF radios is generally restricted to the flight crew members on the flight deck, though the received audio may be played on one of the passenger audio channels.
It is also common for selected UHF, VHF, HF or SATCOM frequencies or channels to be assigned to individual air carriers for administrative traffic that is not directly related to flight control. For example an air carrier may have an HF, VHF, or UHF frequency assigned, commonly called a company frequency, which is used to exchange administrative information (e.g. flight delays, maintenance requirements, and crew assignment information). These company frequencies are also used for plane-to-plane communication between aircraft that are owned by the same air carrier. Flight crew members frequently communicate over or monitor this company frequency, in addition to the primary control frequency.
In conjunction with this flight deck communication capability (UHF, VHF, HF and SATCOM), most commercial aircraft also have a capability in the passenger cabin for access to the public switched telephone network (PSTN). For commercial flights generally within the continental United States, the North American Telephony System (NATS) is an example. In the NATS system, a passenger uses a handset located in the passenger cabin to originate and receive telephone calls while airborne. To accomplish this, the aircraft has a transceiver system that is able to interface with ground terminals which have the ability to interface with the PSTN, thereby connecting a call from the passenger in the aircraft to any telephone number. The NATS system also provides a capability for any telephone user to call a passenger in an aircraft, if they know the appropriate access numbers. Though the NATS system has been used as an example, there are similar systems in other countries with slightly different capabilities.
While most radio communication by the flight crew is concerned with flight control and direction, there are numerous instances where the flight crew has a requirement to exchange administrative information with individuals on the ground who do not have direct access to UHF, VHF, HF or SATCOM radios. Typically, this administrative information is sent over the company radio frequency and is forwarded or relayed by phone to the desired recipient. There are a number of disadvantages to this approach. A first disadvantage is that use of UHF, VHF, HF or SATCOM radios provides no privacy, as the conversation may be overheard by any person with a suitable receiver. A second disadvantage is that only one conversation may be carried on a frequency at a time. Therefore, if a flight crew is sending administrative information on the company HF frequency, no other aircraft may use that frequency until the conversation is complete. Another disadvantage is that if the flight crew chooses to monitor the company frequency for communications that may be directed to them, they must listen to all administrative information that is exchanged, with the associated distraction. Poor transmission quality is a further disadvantages of the flight control system, especially for HF transmissions.
Though both the flight control and passenger communication systems are carried on the same aircraft, flight crew members have not had headset access to a passenger commercial telecommunication system, like the NATS system. There have been proposals to place a NATS handset on the flight deck but unless otherwise modified, use of the handset would require that the flight crew member remove their headset to use the NATS handset. Though not prohibited, this detracts from flight safety and is not an ideal solution.
U.S. Pat. No. 5,568,484 issued to Margis discloses a telecommunications system and method for use on commercial aircraft using local area networks to more easily and efficiently integrate aircraft passenger telecommunications systems with passenger entertainment systems and cabin management systems.
U.S. Pat. No. 4,903,298 issued to Cline discloses an aircraft data communication system with voice encryption that is commonly accessible by either flight crew or passengers. However Cline does not disclose use of a passenger telephone system by the flight crew.
U.S. Pat. No. 3,999,015 issued to Snyder et al. discloses an aircraft communication system providing a plurality of communication paths to interconnect flight crew and passengers. Snyder also discloses connection of external radio transceivers with the flight crew. Snyder does not disclose external communication paths for the flight crew beyond the usual UHF, VHF, HF or SATCOM radio transceivers.
None of the existing capabilities or prior art provide flight crew members with the ability to use the passenger commercial telecommunication system fully integrated with other flight communications.
It is therefore an advantage of the present invention to integrate flight crew access to the passenger commercial communication system, such as NATS, into the communication control panel of the flight deck crew. This advantage may be accomplished, e.g., by providing a selector for each flight deck communication panel that allows transmission and receipt of a telephone conversation using a passenger commercial communication system, such as NATS, through a flight deck headset or its equivalent.
It is another advantage of the present invention to integrate a telephone conversation monitoring capability into the communication control panel of the flight deck crew, where the telephone conversation uses a passenger commercial communication system, such as NATS, and the telephone conversation is intended for the particular flight crew.
It is another advantage of the present invention to provide an ability for the flight crew to originate telephone calls using their flight deck headset, or equivalent, and a means to enter and convert the dialed number into DTMF tones or other similar form as required to connect to the PSTN.
It is another advantage of the present invention to provide an ability for the flight crew to receive telephone calls through a passenger commercial communication system, such as NATS, through their flight deck headset or equivalent, in which these telephone calls are specifically intended for the flight crew, with this ability provided by individual telephone numbers assigned to each aircraft, or similar means to identify the aircraft or aircrew.
These and other advantages of the present invention will become apparent to those of ordinary skill in the art after review of the detailed description, figures and claims of the present invention.